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3T 下基于PSIF 的快速T2 加权腹部成像方法

Fast T2-weighted Abdominal Imaging at 3T Based on PSIF Sequence

  • 摘要: 3T 下传统的屏气 T2 加权成像序列 HASTE 在腹部成像中受到射频特定吸收率和 B1 发射场均匀性的限制。本文研究显示时间反转稳态自由进动快速成像(PSIF)序列在腹部成像中能提供较好的 T2 对比, 并且在翻转角 30°~ 40°之间取得最好的对比度。与 HASTE 对比发现, 该序列 SAR 值低, 且对 B1 发射场均匀性不敏感。实验中, 正常志愿者的肝脏信噪比在 17 左右, 肝脾对比度噪声比在 18 左右, 这对诊断用图像是足够的。此外, PSIF 序列使用很短的 TR 来缩短扫描时间, 采集速度为 1 秒/层, 使得该序列不需要屏气或者呼吸触发。

     

    Abstract: At 3T, conventional breath-hold T2-weighted imaging in the abdomen by HASTE is limited by SAR constraint and B1 inhomogeneity. This work shows that PSIF offers good T2 contrast in abdomen under 3T with a flip angle around 30 to 40 degrees, drastically reducing SAR and is more robust than HASTE. For 2D PSIF in healthy volunteers, the SNR of liver is around 17 and spleen-liver CNR is around 18, which is sufficient for diagnostic purpose. The short TR in PSIF shortens the scan time to 1s per slice, and eliminates the need for breath holding or respiratory triggering.

     

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